The present invention relates to a device for the uniform electrolysis of a metal sheet on both side surfaces thereof. The device is especially useful in a laboratory to produce samples of etched or "grained" metal sheets, especially aluminum sheets. These grained sheets, when produced on a commercial scale, are used as substrates which are coated with a photosensitive composition in the manufacture of lithographic printing plates. By using this laboratory scale device to test various etching or other electrolysis processes, one gains the advantages of less cost, greater ease of operation and greater control as compared to carrying out such development work on a pilot line.
While numerous prior art devices are available for electrolytic processing of metal sheet materials, none are shown to posses all the features and advantages of the present invention with respect to uniformity of etching and repeatability of results.